Methods for treating hypertension and angina using salts of optically pure (-) amplodipine

ABSTRACT

Methods and compositions are disclosed utilizing the optically pure (−) isomer of amlodipine. This compound is a potent drug for the treatment of hypertension while avoiding the concomitant liability of adverse effects associated with the racemic mixture of amlodipine. The (−) isomer of amlodipine is also useful for the treatment of angina and such other conditions as may be related to the activity of (−) amlodipine as a calcium channel antagonist such as cerebral ischemia, cerebral disorders, arrhythmias, cardiac hypertrophy, coronary vasospasm, myocardial infarction, renal impairment and acute renal failure, without the concomitant liability of adverse effects associated with the racemic mixture of amlodipine.

1. BACKGROUND OF THE INVENTION

[0001] This invention relates to novel compositions of matter containingoptically pure (−) amlodipine. These compositions possess potentactivity in treating both systolic and diastolic hypertension whileavoiding adverse effects including but not limited to edema of theextremities, headache and dizziness, which are associated withadministration of the racemic mixture of amlodipine. Additionally, thesenovel compositions of matter containing optically pure (−) amlodipineare useful in treating angina and such other conditions as may berelated to the activity of (−) amlodipine as a calcium channelantagonist including but not limited to cerebral ischemia, cerebraldisorders, arrhythmias, cardiac hypertrophy, coronary vasospasm,myocardial infarction, renal impairment and acute renal failure—whileavoiding the adverse effects associated with administration of theracemic mixture of amlodipine. Also disclosed are methods for treatingthe above-described conditions in a human while avoiding the adverseeffects that are associated with the racemic mixture of amlodipine, byadministering the (−) isomer of amlodipine to said human.

1.1. Steric Relationship and Drug Action

[0002] Many organic compounds exist in optically active forms, i.e.,they have the ability to rotate the plane of plane-polarized light. Indescribing an optically active compound, the prefixes D and L or R and Sare used to denote the absolute configuration of the molecule about itschiral center(s). The prefixes d and l or (+) and (−) are employed todesignate the sign of rotation of plane-polarized light by the compound,with (−) or 1 meaning that the compound is levorotatory. A compoundprefixed with (+) or d is dextrorotatory. For a given chemicalstructure, these compounds, called stereoisomers, are identical exceptthat they are mirror images of one another. A specific stereoisomer mayalso be referred to as an enantiomer, and a mixture of such isomers isoften called an enantiomeric or racemic mixture.

[0003] Stereochemical purity is of importance in the field ofpharmaceuticals, where 12 of the 20 most prescribed drugs exhibitchirality. A case in point is provided by the L-form of the β-adrenergicblocking agent, propranolol, which is known to be 100 times more potentthan the D-enantiomer.

[0004] Furthermore, optical purity is important since certain isomersmay actually be deleterious rather than simply inert. For example, ithas been suggested that the D-enantiomer of thalidomide was a safe andeffective sedative when prescribed for the control of morning sicknessduring pregnancy, while the corresponding L-enantiomer has been thoughtto be a potent teratogen.

[0005] The active compound of this composition and method is an opticalisomer of the compound amlodipine, which is described in Davison et al.,U.S. Pat. No. 4,572,909. Chemically, this (−) isomer is 3-ethyl 5-methyl(−)-2-[(2-aminoethoxy)methyl]-4-(2-chlorophenyl)-1,4-dihydro-6-methyl-3,5-pyridine-dicarboxylate.This isomer will hereinafter be referred to as (−) amlodipine. (−)Amlodipine also includes the substantially optically pure (−) amlodipineisomer.

[0006] Amlodipine, which is the subject of the present invention, isavailable commercially only as the 1:1 racemic mixture. That is, it isavailable only as the 1:1 mixture of optical isomers, calledenantiomers. The racemic mixture of amlodipine that is commerciallyavailable for administration is a besylate salt.

1.2. Pharmacologic Action

[0007] The racemic mixture of amlodipine is in the class of compoundsknown as calcium antagonists. The concept of a specific mechanism ofpharmacologic action related to the antagonism of calcium movement inthe process of excitation-contraction was suggested by Fleckenstein et.al. (see Fleckenstein, A., Calcium Antagonism in Heart and SmoothMuscle:Experimental Facts and Therapeutic Prospects, New York, Wiley,1983; Swamy, V. and D. Triggle, Modern Pharmacology, 2nd. Ed., Craig andStitzel, Eds., Little, Brown and Co., Boston, 1986, Chapt. 26, 373-380;Triggle, D. J., and R. A. Janis, Ann. Rev. Pharm. and Tox. 27: 347-369,1987). Many of the currently available calcium antagonists appear toantagonize the entry of calcium through voltage dependent channels inthe plasma membrane of cells. The pharmacologic class of calciumantagonists consists of chemically diverse compounds. Given thestructural heterogeneity of the class it is likely that thepharmacological action involves more than one site or mechanism ofaction.

[0008] Amlodipine is one of a series of dihydropyridine calciumantagonists. However, amlodipine has a generally slower onset and longerduration of action than, for example, nifedipine. (Jensen, H. et al., J.Hum. Hypertens., 42(5): 541-45, 1990). The metabolites of amlodipineapparently do not possess significant calcium channel blocking activity,while the parent drug offers a biological half-life of some 35-40 hours,prompting a once-daily dosage regimen. (Lorimer, A. R., et al., J. Hum.Hypertens., 3(3): 191-96, 1989; Glasser, S. F. et al., AJH, 2(3):154-57, 1989). Its ability to block, calcium channels in smooth muscleproduces peripheral vasodilation resulting in decreases in both systolicand diastolic blood pressure.

[0009] With regard to the enantiomers of amlodipine, these are disclosedin Arrowsmith et al. J. Med. Chem., 29: 1696-1702 (1986). This referencediscusses in vitro tests to determine calcium antagonist activityagainst calcium-induced constriction of potassium-depolarized rat aorta.The authors allege that in vitro evaluation of the enantiomers ofamlodipine shows the (−) isomer to be twice as active as the racemicmixture in antagonizing calcium-induced constriction ofpotassium-depolarized rat aorta. The authors also allege that the (+)isomer of amlodipine is some 1,000 times less active in these in vitrotests. Further, European Patent Application No. 0 331 315 discloses amethod for separation of the R(−) and S(+) isomers of amlodipine. Whilethese references discuss the enantiomers of amlodipine, they onlyprovide a method of synthesis and in vitro test results of theindividual enantiomer activity as found in rat aorta. There is nodisclosure of the effects of or a suggestion for administering one ofthe enantiomers of amlodipine to a human. Moreover, there is nodisclosure or suggestion of the alleviation or reduction of side effectswhich is achieved by the administration of (−) amlodipine.

[0010] The racemic mixture of amlodipine is presently used primarily asan antihypertensive agent; it is generally taken orally as a once-dailytherapy. As stated above, the racemic mixture of amlodipine producesperipheral vasodilation, resulting in decreases in both systolic anddiastolic blood pressure when used as an antihypertensive agent. Thisantihypertensive effect occurs in the relative absence of significant orsustained effects on cardiac rate.

[0011] While yet the subject of extensive research, hypertension appearsto be the product of an inherited predisposition—coupled with dietary,emotional, and environmental factors, which results in a structuraladaptation of the cardiac muscle and the large blood vessels. Mostpatients display heightened vascular and cardiac reactions tosympathetic nervous stimulation, but the precise relationship ofsympathetic nervous stimulation to the etiology of the disease.Nevertheless, hypertension results in chronic readjustment ofcardiovascular hemodynamics, alteration of blood vessel walls,cardiovascular resistance and regional transmural pressures.

[0012] Pharmacologic management of hypertension is generally directed tothe normalization of altered hemodynamic parameters, and many drugs anddrug classes, either as monotherapy or in combination treatment, canreduce and control elevated blood pressure. However, treatment ofhypertension does not always correspondingly benefit the morbidity andmortality of the condition, either because chronic hypertension hasproduced other significant and irreversible cardiovascular changes, orbecause present drugs have an adverse effect on some other risk factorfor cardiovascular disease. Rather, current drug therapy simply providessustained arterial pressure reduction.

[0013] Furthermore, the racemic mixture of amlodipine is useful intreating other disorders such as angina pectoris.

[0014] Angina pectoris is a highly variable, rather poorly understoodclinical syndrome reflecting a myocardial ischemia. When cardiac work ormyocardial oxygen demand exceeds the ability of the coronary arterialvascular system to supply oxygen, the resulting ischemia stimulates thesensory nerves of the heart, producing the sensation of anginacharacterized by episodes of precordial pressure, discomfort, or asevere, intense crushing pain which may radiate to several sitesincluding the left shoulder and left arm. Physical activity or exertioncharacteristically initiates the condition, and rest or drug therapyrelieves the condition. The signs and symptoms of an episode persist fora few minutes, but can be induced or exaggerated by a meal or exposureto cold air. Treatment is directed to the underlying disease, usuallyatherosclerosis, or to drugs which either reduce myocardial oxygendemand or improve oxygen supply. Calcium antagonists such as amlodipinehave been particularly useful in treating vasospastic angina, the anginaof effort, and the unstable angina, due to the effect of the calciumchannel antagonist on cardiac and vascular smooth muscle.

[0015] Amlodipine may be useful in the treatment of cerebral ischemia.Cerebral ischemia, often the result of atherosclerotic disease orhypertension, results from insufficient cerebral circulation. Undernormal circumstances, an extensive collateral circulation ensuresadequate blood flow. However, cerebral ischemia may result from eitheran intra- or extracranial interruption of arterial blood flow. Ifinterruption is transient, the cerebral tissues recover, and neurologicsymptoms disappear. If the ischemia lasts for a somewhat more extendedperiod, infarction results and the resulting neurologic damage ispermanent. In the case of extended ischemia. resulting in infarction,treatment is directed to the underlying vascular disease, to bloodplatelet aggregation inhibitors, and anticoagulant therapy.

[0016] Because of its activity as a calcium channel antagonist,amlodipine may also be useful in treating cardiac arrhythmias. Cardiacarrhythmias represent a broad, complex group of electrophysiologicdisorders that affect the mechanical properties of the heart andvasculature, altering normal cardiac rhythm, function and output. Normalcardiac rhythm originates with the sinoatrial node, which possesses highintrinsic automaticity. Adequate automaticity and conduction lead toactivation of atrial and ventricular fibers, producing in sequence theelements of normal functional heart beat. Calcium antagonists may be ofvalue in conditions where calcium-related changes in membrane potentialand conduction alter normal rhythm. In the absence of treatment,symptoms vary with individual arrhythmias, but are often the consequenceof inadequate cardiac filling and output and often include fatigue,decreased exercise tolerance, syncope, shortness of breath, nausea,lightheadedness and the like.

[0017] Amlodipine may be useful to treat cardiac hypertrophy. Cardiachypertrophy can result from excessive workload either due to anobstruction to outflow, termed systolic overload, or to excessivevolumes presented to the heart in diastole, termed diastolic overload.Systolic overload results in concentric ventricular hypertrophy, inwhich there is an increased thickness in the walls of the heart notassociated with increased volume. Diastolic overload causes dilation andhypertrophy with an increased blood volume. An inadequate cardiac outputresults from the heart's failure in systolic or diastolic overload,leading to fatigue, shortness of breath, pulmonary congestion, edema andthe like. Calcium channel antagonists effect workload and, as such, maybe useful in treating cardiac hypertrophy due to the effect of thecalcium antagonist on cardiac and vascular smooth muscle in reducingblood pressure.

[0018] It is also possible that amlodipine could be used to treatcoronary arterial spasm. Coronary arterial spasm can occur in theabsence of significant coronary atherosclerosis and is thought to be aninitiating event in variant angina and in myocardial infarction.Coronary spasm may occur without the patient feeling any significantdiscomfort. In an electrically unstable heart, diverse neural impulsesto the heart may provoke coronary vascular spasm. This may result inenhanced myocardial ischemia and arrhythmia, which in turn may culminatein ventricular fibrillation and sudden cardiac death. As in variant orvasospastic angina, the calcium channel antagonists may be of particularusefulness due to their effect on cardiac and vascular smooth muscle.

[0019] Furthermore, amlodipine may be useful in the treatment ofmyocardial infarction, ischemic myocardial necrosis, and ischemiareperfusion injury. Myocardial infarction or ischemic myocardialnecrosis generally results from the abrupt reduction of coronary bloodflow to a portion of the myocardium The condition likely originates fromatherosclerosis of the coronary arteries. Either coronary arteryvasospasm or acute coronary thrombosis precipitates the condition,although the etiology is the subject of continuing research. Myocardialinfarction is predominantly a disease of the left ventricle. Precordialpain and left ventricular dysfunction characterize the disease. Thepain, which can be severe aching or pressure, leads to apprehension.Symptoms include left ventricular heart failure, pulmonary edema, shockor significant cardiac arrhythmia. Calcium channel antagonists may findutility in the management of myocardial infarction patients due to theireffects on coronary artery vasospasm, blood pressure or other effects oncardiac function or vascular smooth muscle.

[0020] Amlodipine may be used to treat congestive heart failure.Congestive heart failure can be caused by hypertension, cardiomyopathy,coronary artery disease or valvular heart disease. Congestive failureresults in poor cardiac output and elevated left-ventricular diastolicpressure, leading to dyspnea, fatigue, peripheral edema, and coughing.The ability of some calcium antagonists to lower afterload by dilatingperipheral arteries without having a significant inotropic effect mayincrease their use in treating congestive heart failure.

[0021] Amlodipine may be of use in treating migraine. Classic migrainetypically begins with visual auras followed by severe headaches, oftenaccompanied by nausea and vomiting. Common migraine has similar symptomswithout the preceding visual aura. The causes of migraine have beenstudied intensely, and are still a matter of debate. The most generallyaccepted cause is hypoxia due to reduced cerebral blood flow. Calciumchannel antagonists have been used for migraine prophylaxis since theycan increase cerebral blood flow.

[0022] Amlodipine may also be useful for treating Raynaud's phenomenon,which is characterized by vascular spasm of the extremities. Thesevasospasms can be caused by cold or stress. A pallor or cyanosis isusually present due to severe constriction of the digital arteries. Thephenomenon is often seen as a secondary disorder with arterial diseasesor connective tissue diseases such as scleroderma, arthritis or lupuserythematosus. Calcium channel antagonists have been shown to beeffective in treating Raynaud's phenomenon.

[0023] Amlodipine may be useful in the treatment of asthma andbronchospasm. Symptoms of asthma—coughing, wheezing, and dyspnea—arecaused by constriction of tracheobronchial smooth muscle. Asthma attackscan be triggered by antigenic stimuli (pollen, dust) or non-antigenicstimuli (exercise, pollution, infection). The response to these stimulilead to secretions of chemical mediators that cause smooth musclecontraction. Calcium channel antagonists can be used to controlbronchoconstriction and relieve asthma attacks.

[0024] In addition, the racemic mixture of amlodipine may be useful totreat renal impairment and acute renal failure. Renal impairment andacute renal failure are clinical conditions of diverse etiology, whichare associated with an increasing azotemia or urea nitrogen in theblood, and often an oliguria or a diminished volume of urine in relationto fluid intake. The pathophysiology may originate prerenally, manifestas inadequate renal perfusion, due to extracellular fluid volumedepletion or cardiac failure. The most common cause of intrinsic renalfailure is prolonged renal ischemia. Postrenal azotemia may beassociated with obstruction or renal glomerular and tubular dysfunction.Laboratory findings disclose progressive azotemia, acidosis,hyperkalemia, and hyponatremia. Factors aggravating kidney impairment orfailure must be specifically treated, including heart failure,obstruction and the like. Moderate or severe hypertension has adeleterious effect on renal function, and management of the hypertensionwith a variety of drugs including calcium channel antagonists may beuseful therapy.

[0025] In addition, the racemic mixture of amlodipine could be useful inthe treatment of cognitive disorders. Cognitive disorders include butare not limited to dementia and age-associated memory impairment.

[0026] Dementia can occur at any age. It is a structurally causedpermanent or progressive decline in several dimensions of intellectualfunction that interferes substantially with individual normal social oreconomic activity.

[0027] One particular type of dementia is Alzheimers-type dementia.Alzheimers-type of dementia is thought to be due to a degenerativeprocess, with a large loss of cells from the cerebral cortex and otherbrain areas. Acetylcholine-transmitting neurons and their target nervecells are particularly affected. The brain shows marked atrophy withwide sulci and dilated ventricles. Senile plaques and neurofibrillarytangles are present. Memory loss is the most prominent early symptom.Disturbances of arousal do not occur early in the course. Alzheimer'spresenile and senile onset dementias are similar in both clinical andpathologic features, with the former commonly beginning in the 5th and6th decades and the latter in the 7th and 8th decades. The dementiausually progresses steadily, becoming well advanced in 2 to 3 years.Some cases of dementia occurring in the presenile period are hard toclassify and are sometimes labelled idiopathic or simple preseniledementia.

[0028] The signs and symptoms of dementia in particular Alzheimers-typedementia include depression, paranoia, anxiety or any of several otherpsychologic symptoms. The most common clinical picture is slowdisintegration of personality and intellect due to impaired insight andjudgment and loss of affect. Memory impairment increases, beginning withproblems recalling recent events or finding names. The impairment variesgreatly from time to time and often from moment to moment. Dementiagenerally is an insidious, slowly progressive, untreatable condition.However, the rate of progression varies widely and depends on the cause.

[0029] Another type of cognitive disorder is age-associated memoryimpairment (AAMI). AAMI is used to describe healthy non-demented peoplewho have experienced memory loss over the course of the person's life.Most commonly it is used to describe adults over the age of 50 who haveexperienced memory loss over the course of adult life. It has beenestimated that between 25% and 50% of people over the age of 65 havethis disorder.

[0030] Many calcium channel antagonists cause significant adverseeffects. These adverse effects include but are not limited totachycardia, orthostatic hypotension and fluid retention. In contrast tothe situation with several other calcium channel antagonists, however,the racemic mixture of amlodipine has not been found to cause eithermarked or prolonged direct effects on heart rate or the reflexconsequence of vasodilation.

[0031] However, the administration of the racemic mixture of amlodipineto a human has been found to cause still other adverse effects. Theseadverse effects include but are not limited to edema of, the extremitiesincluding peripheral edema, headache, flushing/hot flashes, fatigue,vertigo, muscle cramps and dizziness.

[0032] Thus, it would be particularly desirable to find a compound withthe advantages of the racemic mixture of amlodipine which would not havethe aforementioned disadvantages of significant adverse side effects andwhich was useful for treatment of other conditions.

2. SUMMARY OF THE INVENTION

[0033] It has now been discovered that the optically pure (−) isomer ofamlodipine is an effective antihypertensive agent for both systolic anddiastolic hypertension, particularly in mild to moderate disease andangina, while avoiding adverse effects including but not limited toedema of the extremities, headache and dizziness, which are associatedwith the administration of the racemic mixture of amlodipine. It hasalso been discovered that these novel compositions of matter containingoptically pure (−) amlodipine are useful in treating other conditions asmay be related to the activity of (−) amlodipine as a calcium channelantagonist, including but not limited to cerebral ischemia, cerebraldisorders, arrhythmias, cardiac hypertrophy, coronary vasospasm,myocardial infarction, renal impairment and acute renal failure whileavoiding the above-described adverse effects associated with theadministration of the racemic mixture of amlodipine. The presentinvention also includes methods for treating the above-describedconditions in a human while avoiding the adverse effects that areassociated with the racemic mixture of amlodipine by administering the(−) isomer of amlodipine to said human.

3. DETAILED DESCRIPTION OF THE INVENTION

[0034] The present invention encompasses a method of eliciting anantihypertensive effect in a human, while avoiding the concomitantliability of adverse effects, which comprises administering to saidhuman in need of such antihypertensive therapy, an amount of (−)amlodipine or a pharmaceutically acceptable salt thereof, substantiallyfree of its (+) stereoisomer, said amount being sufficient to alleviatehypertension, but insufficient to cause said adverse effects associatedwith administration of racemic amlodipine.

[0035] The present invention also encompasses an antihypertensivecomposition for the treatment of a human in need of antihypertensivetherapy, which comprises an amount of (−) amlodipine or apharmaceutically acceptable salt thereof, substantially free of its (+)stereoisomer, said amount being sufficient to alleviate saidhypertension but insufficient to cause adverse effects of racemicamlodipine.

[0036] The present invention further encompasses a method of treatingangina in a human, while avoiding the concomitant liability of adverseeffects, which comprises administering to said human in need of suchanti-angina therapy, an amount of (−) amlodipine, or a pharmaceuticallyacceptable salt thereof, substantially free of its (+) stereoisomer,said amount being sufficient to alleviate said condition butinsufficient to cause said adverse effects associated withadministration of racemic amlodipine.

[0037] In addition, the present invention encompasses an antianginalcomposition for the treatment of a human having angina, which comprisesan amount of (−) amlodipine or a pharmaceutically acceptable saltthereof, substantially free of its (+) stereoisomer, said amount beingsufficient to alleviate said angina but insufficient to cause adverseeffects of racemic amlodipine.

[0038] A further aspect of the present invention includes a method oftreating a condition caused by excessive calcium influx in cells in ahuman, while avoiding the concomitant liability of adverse effects,which comprises administering to said human in need of a reduction inexcessive calcium influx an amount of (−) amlodipine, or apharmaceutically acceptable salt thereof, substantially free of its (+)stereoisomer, sufficient to alleviate said condition but insufficient tocause said adverse effects of racemic amlodipine. Conditions caused byexcessive calcium influx in cells in a human include but are not limitedto cerebral ischemia, cerebral disorders such as cognitive disordersincluding but not limited to Alzheimer's dementia and memory impairment,arrhythmias, cardiac hypertrophy, congestive heart failure, coronaryvasospasm, migraine, bronchospasm and asthma, Raynaud's phenomenon,myocardial infarction, renal impairment and acute renal failure.

[0039] Furthermore, the present invention includes a composition fortreating a condition caused by excessive calcium influx in cells in ahuman, which comprises an amount of (−) amlodipine, or apharmaceutically acceptable salt thereof, substantially free of its (+)stereoisomer, said amount being sufficient to alleviate said conditionbut insufficient to cause adverse effects of racemic amlodipine.

[0040] The commercially available racemic mixture of amlodipine (e.g., a1:1 racemic mixture of the two enantiomers) causes antihypertensive andantianginal activity; however, this racemic mixture, while offering theexpectation of efficacy, causes adverse effects. Utilizing the (−)isomer of amlodipine results in clearer dose-related definitions ofefficacy, surprisingly diminished adverse effects, and accordingly, animproved therapeutic index. It is, therefore, more desirable to use the(−) isomer of amlodipine.

[0041] The term “adverse effects” includes, but is not limited to,cardiovascular effects (including tachycardia and diminishedcontractility of the heart), edema of the extremities, headache,dizziness, flushing, fatigue, vertigo, and muscle cramps.

[0042] The term “substantially free of its (+) stereoisomer” as usedherein means that the composition contains a greater proportion orpercentage of the (−) isomer of amlodipine in relation to the (+) isomerof amlodipine, said percentage being based on the total amount ofamlodipine. In a preferred embodiment the term “substantially free ofits (+) stereoisomer” means that the composition contains at least 90%by weight of (−) amlodipine, and 10% by weight or less of (+)amlodipine. In the most preferred embodiment the term “substantiallyfree of the (+) stereoisomer” means that the composition contains atleast 99% by weight (−) amlodipine, and 1% or less of (+) amlodipine. Inanother preferred embodiment the term “substantially free of its (+)stereoisomer” as used herein means that the composition contains 100% byweight of (−) amlodipine. The terms “substantially optically pure (−)isomer of amlodipine” and “optically pure (−) isomer of amlodipine arealso encompassed by the above-described meanings.

[0043] The term “eliciting an antihypertensive effect” as used hereinmeans providing a normalization to otherwise elevated systolic and/ordiastolic blood pressure, and by so doing providing relief from anypossible symptoms or other hemodynamic effects caused by the elevatedpressure.

[0044] The term “a method of treating angina” as used herein meansrelief from the symptoms of myocardial ischemia, which include, but arenot limited to, episodes of precordial pressure, discomfort, or a severeintense, crushing pain which may radiate, and which may be accompaniedby changes in respiration, pulse rate, and blood pressure.

[0045] The term, “a condition caused by excessive calcium influx incells in a human” includes but is not limited to conditions involvingcalcium influx in human cell that may be present in smooth muscle,cardiac, and other tissues including lung and brain. These conditionsinclude, but are not limited to, cerebral ischemia, cerebral disorderssuch as cognitive disorders including Alzheimer's dementia and memoryimpairment, arrhythmias, cardiac hypertrophy,, congestive heart failure,coronary vasospasm, migraine, bronchospasm and asthma, Raynaud'sphenomenon, myocardial infarction, renal impairment and acute renalfailure. The symptoms associated with these disorders include, but arenot limited to, the symptoms of precordial discomfort or pain, headache,fatigue, decreased exercise tolerance, syncope, shortness of breath,nausea, lightheadedness, edema, pulmonary congestion, arrhythmia orpalpitation, azotemia, and/or oliguria.

[0046] The chemical synthesis of the racemic mixture of amlodipine canbe performed by the method described in Arrowsmith, J. E. et al., J.Med. Chem., 29: 1696-1702 (1986).

[0047] A technique for separation of the (−) amlodipine isomer from theracemic mixture is illustrated schematically (see Arrowsmith, J. E., EP331,315) as follows:

[0048] The racemic acid 1 is converted to its cinchonidine salts inmethanol solution. Upon dilution with water and standing at roomtemperature, a crystalline precipitate is formed which can besubsequently recrystallized to constant rotation to give thediastereomerically pure cinchonidine salt 2. Further, the mother liquidsfrom the original crystallization can be reduced in volume and stirredat room temperature, e.g. overnight, to afford a fine precipitate whichcan also be recrystallized to give the diastereomerically purecinchonidine salt 2. The cinchonidine salt 2 is partitioned betweenethyl acetate and dilute hydrochloric acid to liberate the (+) acid 3.The acid 3 is then esterified using carbonyldimidazole (CDI) innear-quantitative yield by forming an imidazolide and decomposing theimidazolide with ethanolic sodium ethoxide to give 4. The azido group in4 can then be cleanly reduced to amino by catalytic hydrogenation,giving (−) amlodipine, which is most conveniently isolated as the saltof an acid, e.g. as the maleate 5.

[0049] The magnitude of a prophylactic or therapeutic dose of (−)amlodipine in the acute or chronic management of disease will vary withthe severity of the condition to be treated and the route ofadministration. The dose, and perhaps the dose frequency, will also varyaccording to the age, body weight, and response of the individualpatient. In general, the total daily dose ranges, for the conditionsdescribed herein, is from about 0.01 mg. to about 100.0 mg. Preferably,a daily dose range should be between about 0.5 mg to about 20.0 mg.while most preferably, a daily dose range should be between about 0.5 mgto about 10 mg. In managing the patient, the therapy should be initiatedat a lower dose, perhaps about 0.025 mg to about 2.5 mg and increased upto about 20 mg or higher depending on the patient's global response. Itis further recommended that children and patients over 65 years, andthose with impaired renal or hepatic function, initially receive lowdoses, and that they be titrated based on global response and bloodlevel. It may be necessary to use dosages outside these ranges in somecases.

[0050] The various terms, “an amount sufficient to alleviatehypertension but insufficient to cause said adverse effects, “an amountsufficient to alleviate said condition but insufficient to cause saidadverse effects” wherein said condition is angina; and “an amountsufficient to alleviate said condition but insufficient to cause saidadverse effects” wherein said condition includes but is not limited tocerebral ischemia, cerebral disorders, arrhythmias, cardiac hypertrophy,coronary vasospasm, myocardial infarction, renal impairment and acuterenal failure are encompassed by the above described dosage amounts anddose frequency schedule.

[0051] Any suitable route of administration may be employed forproviding the patient with an effective dosage of (−) amlodipine. Forexample, oral, rectal, parenteral, transdermal, subcutaneous,intramuscular, and the like may be employed. Dosage forms includetablets, troches, dispersions, suspensions, solutions, capsules,patches, and the like.

[0052] The pharmaceutical compositions of the present invention comprise(−) amlodipine as active ingredient, or a pharmaceutically acceptablesalt thereof, and may also contain a pharmaceutically acceptablecarrier, and optionally, other therapeutic ingredients.

[0053] The term “pharmaceutically acceptable salts” refers to saltsprepared from pharmaceutically acceptable non-toxic acids includinginorganic acids and organic acids.

[0054] Since the compound of the present invention is basic, salts maybe prepared from pharmaceutically acceptable non-toxic acids includinginorganic and organic acids. Such acids include acetic, benzene-sulfonic(besylate), benzoic, camphorsulfonic, citric, ethenesulfonic, fumaric,gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic,maleic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic,pantothenic, phosphoric, succinic, sulfuric, tartaric acid,p-toluenesulfonic, and the like. Particularly preferred are besylate,hydrobromic, hydrochloric, phosphoric and sulfuric acids. (See Campbell,S. F. et al., U.S. Pat. No. 4,806,557.)

[0055] The compositions include compositions suitable for oral, rectaland parenteral (including subcutaneous, intramuscular, and intravenous)administration, although the most suitable route in any given case willdepend on the nature and severity of the condition being treated. Themost preferred route of the present invention is the oral route. Thecompositions may be conveniently presented in unit dosage form, andprepared by any of the methods well known in the art of pharmacy.

[0056] In the case where an oral composition is employed, a suitabledosage range for use is from about 0.01 mg. to about 100.0 mg. totaldaily dose, given as a once daily administration in the morning or individed doses if required. Preferably, a dose range of between about 0.5mg to about 20.0 mg is given as a once daily administration or individed doses if required, and most preferably a dose range of frombetween about 0.5 mg to about 10.0 mg is given as a once dailyadministration or in divided doses if required. Patients may be upwardtitrated from below to within this dose range to a satisfactory controlof symptoms or blood pressure as appropriate.

[0057] In practical use, (−) amlodipine can be combined as the activeingredient in intimate admixture with a pharmaceutical carrier accordingto conventional pharmaceutical compounding techniques. The carrier maytake a wide variety of forms depending on the form of the preparationdesired for administration, e.g., oral or parenteral (includingintravenous injections or infusions). In preparing the compositions fororal dosage form any of the usual pharmaceutical media may be employed.Usual pharmaceutical media include, for example, water, glycols, oils,alcohols, flavoring agents, preservatives, coloring agents, and the likein the case of oral liquid preparations (such as for example,suspensions, solutions, and elixirs); aerosols; or carriers such asstarches, sugars, microcrystalline cellulose, diluents, granulatingagents, lubricants, binders, disintegrating agents and the like, in thecase of oral solid preparations (such as for example, powders, capsules,and tablets) with the oral solid preparations being preferred over theoral liquid preparations. The most preferred oral solid preparation istablets.

[0058] Because of their ease of administration, tablets and capsulesrepresent the most advantageous; oral dosage unit form, in which casesolid pharmaceutical carriers are employed. If desired, tablets may becoated by standard aqueous or nonaqueous techniques.

[0059] In addition to the common dosage forms set out above, thecompounds of the present invention may also be administered bycontrolled release means and/or delivery devices such as those describedin U.S. Pat. Nos. 3,845,770; 3,916,899; 3,536,809; 3,598,123; and4,008,719, the disclosures of which are hereby incorporated byreference.

[0060] Pharmaceutical compositions of the present; invention suitablefor oral administration may be presented as discrete units such ascapsules, cachets, or tablets, or aerosols sprays, each containing apredetermined amount of the active ingredient, as a powder or granules,or as a solution or a suspension in an aqueous liquid, a non-aqueousliquid, an oil-in-water emulsion, or a water-in-oil liquid emulsion.Such compositions may be prepared by any of the methods of pharmacy, butall methods include the step of bringing into association the activeingredient with the carrier which constitutes one or more necessaryingredients. In general, the compositions are prepared by uniformly andintimately admixing the active ingredient with liquid carriers or finelydivided solid carriers or both, and then, if necessary, shaping theproduct into the desired presentation.

[0061] For example, a tablet may be prepared by compression or molding,optionally, with one or more accessory ingredients. Compressed tabletsmay be prepared by compressing in a suitable machine the activeingredient in a free-flowing form such as powder or granules, optionallymixed with a binder, lubricant, inert diluent, and/or surface active ordispersing agent. Molded tablets may be made by molding in a suitablemachine a mixture of the powdered compound moistened with an inertliquid diluent. Desirably, each tablet contains from about 0.01 mg toabout 50 mg of the active ingredient, and each cachet or capsulecontains from about 0.5 mg to about 50 mg of the active ingredient, (−)amlodipine. Most preferably, the tablet, cachet or capsule containseither one of three dosages, 0.5 mg, 2.5 mg and 5.0 mg (as scoredtablets, the preferable dose form) of the active ingredient.

[0062] The invention is further defined by reference to the followingexamples describing in detail the testing and preparation of thecompositions of the present invention. It will be apparent to thoseskilled in the art, that many modifications, both to materials andmethods, may be practiced without departing from the purpose andinterest of this invention.

4. EXAMPLES 4.1. Example 1 Vascular Selectivity Studies

[0063] The relative potency of optically pure (−) amlodipine and racemicamlodipine as calcium channel antagonists and negative inotropic agentsare determined by a pharmacological study. Evaluation of these compoundsand others in in vitro test systems provide results, from which thevascular selectivity of a particular compound can be assessed. Calciumchannel antagonist activity of the compounds as a function of theirmolar concentration can be evaluated by measuring their inhibition ofthe calcium-induced contraction of strips of rat aorta immersed in abath of Krebs-Henseleit buffer containing 45 mM K⁺ and no Ca²⁺. In thepresence of various concentrations of the antagonists, inhibition wouldoccur in the contraction of this isolated tissue preparation in responseto the addition of calcium chloride. Antagonists may be compared byexamining the molar concentration of compounds inhibiting thecalcium-induced contraction by 50%.

[0064] As an index of cardiac depression, negative inotropic activitymay be comparably assessed using isolated heart preparations of adultrats. The tissues are prepared and perfused in vitro withKrebs-Henseleit buffer solution, with the activity of the calciumchannel antagonists evaluated as a function of their concentration. Thecompounds are tested for their ability to alter cardiac contraction.Relative potency is calculated from the IC₂₅ values of the compounds,i.e., the concentration required to depress contraction by 25%.

4.2. Example 2 Radioligand Binding Studies

[0065] Hind limb skeletal muscles from rats or guinea pigs are mincedand homogenized. After filtration and repeated centrifugation, thepellet is homogenized and diluted in a Tris buffer to a proteinconcentration of 1-3 mg/ml. Volumes of this suspension containing 3-10μg protein are incubated in the presence of a fixed concentration of 0.2to 0.5 nM (+)-[³H]-isradipine or a similar radioactive ligand andincreasing concentrations of racemic amlodipine, (−) amlodipine or (+)amlodipine. After 1 hour incubation, the bound and free radioactivity ismeasured in a scintillation counter and the affinity of the testcompounds to the receptors is calculated.

4.3. Example 3 Effects on Coronary Vascular Resistance in the Guinea PigLangendorff Heart Preparation

[0066] Male guinea pigs weighing between 400 and 450 g are killed bycervical dislocation. The hearts are removed and perfused withKrebs-Henseleit solution at constant pressure (60 cm water) by means ofretrograde cannulation of the aorta in a Langendorff apparatus. TheKrebs-Henseleit solution, consisting of 118.0 mM NaCl, 4.7 mM KCl, 5.5mM CaCl₂, 1.2 nM MgSO₄, 25.0 mM NaHCO₃ and 5.0 mM glucose, is prewarmedto 37° C. and gassed with a mixture of 95% oxygen/5% carbon dioxide. Aballoon catheter connected to a pressure transducer is placed in theleft ventricle via the left atrium and is preloaded to a pressure of 40mm Hg. Coronary perfusate flow is measured continuously, and changes inheart rate and left ventricular contractility are also monitoredcontinuously.

[0067] Each experiment consists of a 30 minute equilibrium period duringwhich coronary flow is stabilized at 9-12 ml/min. Following this period,a vasoconstrictor is injected 3 times at 40 minute intervals into thecannulated aorta. This dose of U-46619 (9,11-methanoepoxy-PGH₂) evokesapproximately a 75% decrease in coronary flow within 30-40 sec, and theeffect is fully reversible after 20-25 min continuous perfusion. Racemicamlodipine, (−) amlodipine or (+) amlodipine dissolved in dimethylsulfoxide or the vehicle are injected in increasing concentrations priorto further U-46619 injections.

[0068] The mean decrease in coronary flow obtained with threeconsecutive injections of U-46619 in the absence of the test substanceis taken to be 100% and the percent inhibition of this effect in thepresence of increasing concentrations of the test drugs is calculated.Complete individual dose-response curves for each test drug aregenerated in five hearts, enabling the calculation of the dose for thehalf-maximal antivasoconstrictor effect (ID₅₀).

4.4. Example 4 Antihypertensive Efficacy in Spontaneously HypertensiveRats

[0069] Male spontaneously hypertensive rats (300-350 g) areanesthetized, and polyethylene catheters are implanted in the abdominalaorta via a femoral artery, and in the abdominal vena cava via a femoralvein. The arterial catheters are connected to pressure transducers bymeans of an intraflow device, flushing the catheters with 3 ml/hr. Meanarterial pressures are derived electronically from the blood pressurewave. Mean pretreatment values of mean arterial pressure are in therange of 160-220 mm Hg. Doses of racemic amlodipine, (−) amlodipine and(+) amlodipine, or of the solvent vehicle, are injected into the venouscatheter. Responses in mean arterial pressure to the respective drug orsolvent are registered and the relative potencies of the test compoundsare calculated.

4.5. Example 5 Cardiovascular

[0070] Calcium Antagonism, Guinea Pig Ileum (In Vitro):

[0071] Test substance (3 μg/ml) inhibition of the contractile responseof the K⁺-depolarized isolated guinea pig ileal segment, bathed inCa-free physiological salt solution at 37° C., to added calcium (20μg/ml of CaCl), indicates calcium antagonist activity.

[0072] Reference Agents (ED₁₀₀,μg/ml): atropine >2 isoxuprine 4cinnazrizine 1 mepyramine >5 cyproheptadine 0.025 nifedipine 0.001diltiazem 0.01 papaverine 4 diphenhydramine 1 promethazine 0.25flunarizine 0.1 propranolol 4 ipratropium bromide >2 verapamil 0.01

4.6. Example 6 Studies on Insulin Resistance

[0073] Insulin is a hormone that activates various biochemical processesin the body, the most well known being facilitation of glucose transportover cell membranes and activation of cell growth. The development ofinsulin resistance is common both in diabetics and nondiabetics, but itis only the glucose transport system that develops resistance toinsulin. To compensate for the impaired glucose transport, the normalbody produces more insulin and the diabetic patient has to inject higherdoses of insulin. Since insulin also is a growth hormone, the increasedinsulin concentration induces an accelerated growth of atheroscleroticlesions and increased risk for cardiovascular morbidity and mortality.

[0074] The present studies are performed in old, spontaneouslyhypertensive rats (SHRs), which are known to develop insulin resistance.Racemic amlodipine, (−) amlodipine, and (+) amlodipine are studied fortheir effects on glucose transport, insulin plasma concentration andarterial blood pressure.

[0075] Prior to receiving vehicle or test compound, basal measurementsof the following parameters are made: (1) systolic blood pressure(measured via tail cuff occlusion); (2) fasting levels of plasma insulinand triglycerides; and (3) glucose tolerance.

[0076] The SHRs receive vehicle or test compound via oral gavage once ortwice daily for two or four weeks. Measurements of blood pressure,circulating insulin and triglycerides, and glucose clearance are madefollowing two (and four) weeks of drug administration. Any changes ininsulin resistance resulting from the drug treatment are evident aschanges in the ratio of plasma glucose/plasma insulin levels and fromthe glucose tolerance tests.

4.7. Example 7 Oral Formulation

[0077] Capsules: Quantity per capsule, in mg. Formula A B C Activeingredient 0.5 2.5 5.0 (-) Amlodipine Lactose 83.5 81.5 79.0 Corn Starch15.0 15.0 15.0 Magnesium Stearate 1.0 1.0 1.0 Compression weight 100.0100.0 100.0

[0078] The active ingredient, (−) amlodipine, lactose, and corn starchare blended until uniform; then the magnesium stearate is blended intothe resulting powder. The resulting mixture is encapsulated intosuitably sized two-piece hard gelatin capsules.

4.8. Example 8 Oral Formulation

[0079] Tablets Quantity per tablet in Gm. Formula A B C Activeingredient 0.5 2.5 5.0 (-) Amlodipine lactose BP 183.0 181.0 178.5starch BP 15.0 15.0 15.0 Pregelatinized Maize Starch BP magnesiumstearate 1.5 1.5 1.5 Compression Weight 200.0 200.0 200.0

[0080] The active ingredient, (−) amlodipine, is sieved through asuitable sieve and blended with lactose, starch, and pregelatinizedmaize starch. Suitable volumes of purified water are added and thepowders are granulated. After drying, the granules are screened andblended with the magnesium stearate. The granules are then compressedinto tablets using 7 mm diameter of punches.

[0081] Tablets of other strengths may be prepared by altering the ratioof active ingredient to lactose or the compression weight and usingpunches to suit.

What is claimed is:
 1. A method of eliciting an antihypertensive effectin a human, while avoiding the concomitant liability of adverse effectsassociated with administration of racemic amlodipine, which comprisesadministering to said human in need of antihypertensive therapy, anamount of (−)amlodipine, or a pharmaceutically acceptable salt thereof,substantially free of its (+) stereoisomer, said amount being sufficientto alleviate said hypertension but insufficient to cause said adverseeffects of racemic amlodipine.
 2. The method of claim 1 wherein (−)amlodipine is administered by intravenous infusion, by transdermaldelivery, or orally as a tablet or a capsule.
 3. The method of claim 2wherein the amount administered is from about 0.01 mg to about 100.0 mgdaily.
 4. The method of claim 3 wherein the amount administered is fromabout 0.5 mg to about 20 mg.
 5. The method of claim 4 wherein the amountadministered is from about 0.5 mg to about 10.0 mg.
 6. The method ofclaim 1 wherein the amount of (−) amlodipine or a pharmaceuticallyacceptable salt thereof is greater than approximately 90% by weight ofthe total amount of amlodipine.
 7. The method of claim 1 wherein theamount of (−) amlodipine or a pharmaceutically acceptable salt thereof,substantially free of its (+) stereoisomer, is administered togetherwith a pharmaceutically acceptable carrier.
 8. The method according toclaims 2, 3, 4, 5, or 6, wherein (−) amlodipine is administered as itsbesylate salt.
 9. An antihypertensive composition for the treatment of ahuman in need of antihypertensive therapy which comprises, an amount of(−) amlodipine or a pharmaceutically acceptable salt thereof,substantially free of its (+) stereoisomer, said amount being sufficientto alleviate said hypertension, but insufficient to cause adverseaffects of racemic amlodipine.
 10. A composition according to claim 9wherein the amount is about 0.01 mg to about 100.0 mg.
 11. A compositionaccording to claim 10 wherein said composition is administered from oneto four times a day.
 12. A composition according to claim 11 whereinsaid composition is administered once a day.
 13. A composition accordingto claim 10 which comprises (−) amlodipine besylate.
 14. A compositionaccording to claim 13 wherein said composition is adapted for oraladministration.
 15. A composition according to claim 13 adapted forintravenous delivery.
 16. A composition according to claim 13 for use ina transdermal formulation.
 17. A composition according to claim 16 foruse as a transdermal patch.
 18. The composition according to claim 9wherein (−) amlodipine or a pharmaceutically acceptable salt thereof,substantially free of its (+) stereoisomer, is administered togetherwith a pharmaceutically acceptable carrier.
 19. A method of treatingangina in a human, while avoiding the concomitant liability of adverseeffects associated with administration of racemic amlodipine, whichcomprises administering to said human in need of such anti-anginatherapy an amount of (−) amlodipine, or a pharmaceutically acceptable,salt: thereof, substantially free of its (+) stereoisomer, said amountbeing sufficient to alleviate said condition but insufficient to causesaid adverse effects.
 20. The method of claim 19 wherein (−) amlodipineis administered by intravenous infusion, by transdermal delivery, ororally as a tablet or a capsule.
 21. The method of claim 20 wherein theamount administered is from about 0.01 mg to about 100.0 mg.
 22. Themethod of claim 21 wherein the amount administered is from about 0.5 mgto about 20.0 mg.
 23. The method of claim 22 wherein the amountadministered is from about 0.5 mg to about 10.0 mg.
 24. The method ofclaim 19 wherein the amount of (−) amlodipine or a pharmaceuticallyacceptable salt thereof is greater than approximately 90% by weight ofthe total amount of amlodipine.
 25. The method of claim 19 wherein theamount of (−) amlodipine or a pharmaceutically acceptable salt thereof,substantially free of its (+) stereoisomer, is administered togetherwith a pharmaceutically acceptable carrier.
 26. The method according toclaims 20, 21, 22, 23 or 24 wherein (−) amlodipine besylate isadministered.
 27. An antianginal composition for the treatment of ahuman having angina which comprises, an amount of (−) amlodipine or apharmaceutically acceptable salt thereof, substantially free of its (+)stereoisomer, said amount being sufficient to alleviate said angina butinsufficient to cause. adverse effects of racemic amlodipine.
 28. Acomposition according to claim 27 wherein the amount is about 0.01 mg toabout 100.0 mg.
 29. A composition according to claim 28 wherein saidcomposition is administered from one to four times a day.
 30. Acomposition according to claim 29 wherein said composition isadministered once a day.
 31. A composition according to claim 28 whichcomprises (−) amlodipine besylate.
 32. A composition according to claim31 wherein said composition is adapted for oral administration.
 33. Acomposition according to claim 31 adapted for intravenous delivery. 34.A composition according to claim 31 for use in a transdermalformulation.
 35. A composition according to claim 34 for use as atransdermal patch.
 36. The composition according to claim 27 wherein (−)amlodipine or a pharmaceutically acceptable salt thereof, substantiallyfree of its (+) stereoisomer, is administered together with apharmaceutically acceptable carrier.
 37. A method of treating acondition caused by excessive calcium influx in cells in a human, whileavoiding the concomitant liability of adverse effects associated withadministration of racemic amlodipine, which comprises administering tosaid human in need of such therapy, an amount of (−) amlodipine, or apharmaceutically acceptable salt thereof, substantially free of its (+)stereoisomer, said amount being sufficient to alleviate said conditionbut insufficient to cause said adverse effects.
 38. The method accordingto claim 37 wherein said condition caused by excessive calcium influx incells in a human is selected from the group consisting of cerebralischemia, cerebral disorders, cognitive disorders, Alzheimer's dementia,memory impairment, arrhythmias, cardiac hypertrophy, congestive heartfailure, coronary vasospasm, migraine, bronchospasm and asthma,Raynaud's phenomenon, myocardial infarction, renal impairment and acuterenal failure.
 39. The method of claim 37 wherein (−) amlodipine isadministered by intravenous infusion, by transdermal delivery, or orallyas a tablet or a capsule.
 40. The method of claim 39 wherein the amountadministered is from about 0.01 mg to about 100.0 mg.
 41. The method ofclaim 40 wherein the amount administered is from about 0.5 mg to about20 mg.
 42. The method of claim 41 wherein the amount administered isfrom about 0.5 mg to about 10.0 mg.
 43. The method of claim 37 , whereinthe amount of (−) amlodipine or a pharmaceutically acceptable saltthereof is greater than approximately 90% by weight the total amount ofamlodipine.
 44. The method of claim 37 wherein the amount of (−)amlodipine or a pharmaceutically acceptable salt thereof, substantiallyfree of its (+) stereoisomer is administered together with apharmaceutically acceptable carrier.
 45. The method according to claim39 , 40 , 41, 42 or 43, wherein (−) amlodipine besylate is administered.46. A composition for treating a condition caused by excessive calciuminflux in cells in a human which comprises an amount of (−) amlodipineor a pharmaceutically acceptable salt thereof, substantially free of its(+) stereoisomer, said amount being sufficient to alleviate saidcondition, but insufficient to cause adverse effects of racemicamlodipine.
 47. A composition according to claim 46 wherein saidcondition caused by excessive calcium influx in cells in a human isselected from the group consisting of cerebral ischemia, cerebraldisorders, cognitive disorders, Alzheimer's dementia, memory impairment,arrhythmias, cardiac hypertrophy, congestive heart failure, coronaryvasospasm, migraine, bronchospasm and asthma, Raynaud's phenomenon,myocardial infarction, renal impairment and acute renal failure.
 48. Acomposition according to claim 46 wherein the amount is about 0.01 mg toabout 100.0 mg.
 49. A composition according to claim 48 wherein saidcomposition is administered from one to four times a day.
 50. Acomposition according to claim 49 wherein said composition isadministered once a day.
 51. A composition according to claim 48 whichcomprises (−) amlodipine besylate.
 52. A composition according to claim51 wherein said composition is adapted for oral administration.
 53. Acomposition according to claim 51 adapted for intravenous delivery. 54.A composition according to claim 51 for use in a transdermalformulation.
 55. A composition according to claim 54 for use as atransdermal patch.
 56. The composition according to claim 46 wherein (−)amlodipine or a pharmaceutically acceptable salt thereof, substantiallyfree of its (+) stereoisomer is administered together with apharmaceutically acceptable carrier.